Process of refining sugar from refuse molasses



Patented May 13, 1924.

NITED STATES PATENT OFFICE.

HEIBER C. CUTLER, OF SALT LAKE CITY, UTAH, ASSIGNOR TO UNITED STATES SYRUP COMPANY, A CORPORATION OF UTAH.

PROCESS OI REFINING SUGAR FROM REFUSE MOLASSIS.

No Drawing.

T 0 ((71 whom it may concern:

Be it known that I, HEBER C. CUTLER, a citizen of the United States, residing at Salt Lake City, in the county of Salt Lake and State of Utah, have invented a new and useful Process of Refining Sugar from Refuse Molasses; and I do hereby declare the following to be a full, clear, and exact description of the same.

The object of the present invention is to provide a method of increasing the yield of sugar as such from the usual sources, as beet or cane juices, by adding to the mass at some stage a sufficient amount of acid to render recoverable a proportion of the sugar content that could not be secured in the absence of the acid. Enormous quantities of beet and cane molasses are treated as refuse and utilized only in the manufacture of industrial alcohol, or of stock foods, or are used as fuel, in spite of the fact that the actual sugar content of such molasses may run as high as fifty per cent, this waste being due to a belief that the sucrose could not be obtained either as crystalline sugar or as table sirup, since the sugar content was thought permanently held in combination by the various organic and inorganic impurities which contaminate the mass.

It is my intention to add the acid to the juice or mass at some stage in the process, preferably adding the acid to the refuse molasses after all the sugar usually obtainable has been removed. I may, however, add the acid to the juices or to the sugar fillmass and thereby secure a greater yield by the practice of the usual steps and consequently I do not wish the invention limited except by the claims herewith.

The preferred method, briefly stated, includes the breaking up' and separating of the sugar content of refuse molasses by the adding of a strong mineral acid to release the sucrose from the organic and inorganic impurities present and to reduce the viscosity; separating out the impurities by dialysis; removing the calicum salts; evaporating the mixture; crystallizin'g out the brown sugar; spinning in the centrifugal;

boiling in the vacuum pan; and finally separating out the white sugar.

While the process herein outlined is apphcable to all kinds of beet molasses, sugar Application filed August 21, 1922. Serial No. 583,383.

fillmass, beet juices and like substances, it should be remembered that there can be no arbitrarily set 1 rule for the refiningof molasses or for the recovery of sugar therefrom in consequence of the great variation of composition of the raw material from the different locations. It will naturally, therefore, be necessary to give attention to the chemical composition of the impurities present and to the method of operation of the particular factory producing the molasses,

ut with due care to these details the process may be applied to any kind of molasses by those skilled in the art.

The first step should be to test the material to determine its degreeof alkaline reaction. It may be that the material shows a slightly acid reaction, in which case it is impossible to use sufiiient acid to secure the desired results because acid inverts the sucrose and prevents its recovery as crystals. As far as I know there is no practical method of obtaining table sugar from inverted sucrose and hence I desire to avoid all inversion. This I accomplishby adding to the material indicating an acid reaction, some alkaline substance such as milk of lime or sodium carbonate until the reaction is decidedly alkaline and then add the acid as in the usual process.

' With the usual strong alkaline reaction material, or the material treated as in the previous paragraph, the molasses is first eated to the boiling point and is then introduced into a mixing tank together with a quantity of a strong mineral acid, preferably hydrochloric acid, sufiicient to neutralize the bases present, the amount vary.

ing with the various kinds of molasses and running as highas three per cent of the weight of the material to be treated. The purpose of adding the acid is to reduce the viscosity of the mass and to bring about a chemical change in the several organic transferred to the osmosis supply tank either by pump or by gravity, the latter usually being quite as convenient and is considerably cheaper to operate. It may be desirable, and especiall with beet molasses resulting from the Ste ens process, to filter the solution before transferring it to the osmose supply tank, as the precipitate due to the acid treatment is so heavy as to clog the osmosis press and sometimes break the parchment paper in the osmosis press. The osmosis press may be of any desired type. The action in the osmosis press is quiteas usual, except for the fact that since the mpurities have been rendered more susceptible to the osmosis action by reason of the chemical changes brought about by the action of the acid, the action is much quicker, that 1s, the press will handle a considerably greater quantity of the-molasses in a given time. I find that I can increase the normal capacity of the press by thirty per cent or more and still obtain very much better results than without using acid.

It sometimes happens that the materialin passing through the osmosis press acquires a slight acid reaction, and in such casethe acid should be promptly neutralized by the addition of a suitable alkaline material such as sodium carbonate in order to insure the absence of free acid before proceeding with the next step of the process,

i. e., filtering, and thereby preventing the.

breaking up of any of the sucrose into fructose and dextrose.

The osmosis treatment does not remove 'all the calcium if it is present in the molasses and hence it is preferable to add at this time (although it may be added later on in the process, if desired) a suflicient quantity of phosphoric acid to combine with the calcium present and also to add a small amount of a material, such as kieselguhr or the commercial material sold under the trade name filter-eel which is a plankton marine diatomaceous earth obtained from deposits located at Lompoc, California. The dialysis operation is not an essential step in my process in treating all kinds of molasses, sugar juices, fillmass, etc., but is nevertheless a very desirable one, as it not only removes much of the inorganic salts, but it dilutes the molasses to a convenient degree with purewater. I do not wish, however, the invention to be limited to a process necessarily including this step, except with respect to such of the claims as definitely recite this step.

From the dialyzing or osmosis apparatus, the mixture, which now contains approximately eight per cent of water and is either neutra or gives a slight alkaline reaction, passes by gravity or otherwise to a filter press of any of the standard types commonly used in sugar factories, where the cloudiness that is noticeable in the osmosed sirup is entirely eliminated. This cloudiness is due to the presence of suspended particles of compounds precipitated by the action of the acid and the heating of the mixture and is consequently removed by filtration which leaves the sirup clear and of a higher purity, but still containing in solution certain volatile impurities which are removed by the high temperature in the first body of evaporators. In these evaporators to which the mixture is taken from the filter press, the density is lowered to the degree desired by the operator, the amount of decrease depending largely upon personal wishes and varying from fifty-five to seventy-five degrees Brix. By virtue of the acid treatment a very considerably greater per cent of volatile impurities are eliminated than would ordinarily be driven off.

In the first stages of boiling in the evaporators, it is preferable to add pure water from time to time to keep the water content at approximately eighty per cent in order to purify more readily and effectively the mixture of volatile matter and traces of acid. This is not absolutely necessary, but will improve results and should be left to the discretion of the operator. This boiling may be done in open kettles or other receptacles at atmospheric pressure, but is preferably accomplished in a closed vesselunder pressure and at a consequently higher temperature. During such boiling, which is continued until little or no odors are given off, a marked coagulation of arganic albuminoids may be noted, these impurities separatin out in such form as to be readily removed by some subsequent treatment. If the phosphoric acid has not yet been added to precipitate out the calcium it should be added here, before filtering out the albuminoids.

After removing the coagulated impurities, from the concentrated and purified mixture from the last body of the evaporators, it is now passed to the usual storage tanks and later is boiled to fillmass usually with the addition of a quantity of higher purity material prior to boiling.

After being crystallized in the crystallizer the fillmass is transferred tothe mixer for the centrifugal machine and is spun in the usual way in the centrifugal, the green sirup being taken back and introduced in the second fillmass, the wash sirup boiled back in the first fillmass, and the brown sugar is introduced direct into the sugar melter where it is dissolved to a heavy sirup to which lime milk is added in quantity sufficient to bring the material to a strong alkaline condition, the exact amount dependin on'the quality of the material treated. 1% desired, the lime may be added at the sulfur station instead, the purpose of this treatment is to permit the use of sulphurous acid gas to improve the color and reduce the viscosity of the material.

Boiling to fillmass should be preceded by filtration and it is preferable to add a filtersugar making campaign, by using an independent evaporator to concentrate the ma terial from the osmogenes. The sirup thus concentrated may then be used by mixing the same with the regular materials used for second fillmass.

What I claim is:

1. The step in the process of removing impurities from molasses, which consists in mixing the heated molasses preparatory to obtaining sugar therefrom with a quantity of hydrochloric acid suflicient to neutralize substantially all the alkaline constituents of the molasses.

2. The process of purifying a sucrose containing mixture contaminated with saline impurities and organic matter, in order to obtain crystalline sugar therefrom, which consists in adding to the mixture a quantity of hydrochloric acid sutiicient to substantially neutralize the alkaline impurities, removing the soluble impurities by osmosis, filtering out the solid matter precipitated by the acid, and then boiling off the volatile impurities.

3. The process of purifying a sucrose containing mixture contaminated with saline impurities and organic matter, in order to obtain crystalline sugar therefrom, which consists in adding to the mixture a quantity of hydrochloric acid sufficient to substantially neutralize the alkaline impurities, removing the soluble impurities by osmosis, filtering out the solid matter precipitated by the acid, boiling under pressure to remove volatile impurities and to coagulate such organic albuminoids as may be present, adding Water during boiling to maintain the water content to approximately eighty per cent, and in separating out such coagulated albuminoids.

4. The process of increasing the yield of crystalline sugar from a sucrose containing mixture, which consists in heating the mixture to approximately the boilingpoint of water, adding to the heated mixture a quantity of hydrochloric acid to give a substantially neutral reaction, filtering out the impurities precipitated by the acid, boiling off the volatile impurities, and finally crystallizing out the sugar.

5. In the process of obtaining sugar from molasses, the step of coagulating organic albuminoids which consists in adding to the molasses a quantity of hydrochloric acid sufficient to neutralize substantially all the alkaline impurities present, intimately mixing the acid and molasses, diluting with water, removing the soluble impurities, removing the impurities precipitated by the acid, and in boiling the filtrate to coagulate the albuminoids and in filtering out the coagulated albuminoids.

6. In the process of obtaining sugar from molasses of beet origin, the step of coagulating organic albuminoids which consists in adding to the molasses a quantity of hydrochloric acid suflicient to neutralize substantially all the alkaline impurities present, in-

timately mixing the acid and molasses, di-

luting with water, removing the soluble impurities, removing the. impurities precipitated by the acid and inboiling the filtrate to coagulate the albuminoids and in filtering out the coagulated albuminoids.

7. The process of purifying a sucrose containing mixture contaminated with saline impurities and organic matter, which consists in adding to the mixture a quantit of hydrochloric acid sufiicient to substantially neutralize the alkaline impurities, removing the soluble impurities by osmosis, filtering out the solid matter precipitated by the acid, and then boiling off the volatile impurities.

8. The process of obtaining sugar from beet molasses, which consists in rapidly agitating the molasses while heated to about 100 C. with a quantity of hydrochloric acid just insufiicient to invert the sucrose present, removing the soluble impurities, diluting the mixture, boiling until. no odors are given off, adding phosphoric acidsuiiic ent to precipitate out the calcium containing 1mpurities, filtering and clarifying the mixture, concentrating the resulting sirup, and recovering the sugar as crystals.

9. The process of obtaining sugar from beet molasses, which consists in adding to the molasses an alkaline substance to render the reaction decidedly basic, heating the mixture, substantially neutralizing the reaction with hydrochloric acid while intimately mixing the molasses and the acid, dialyzing the mixture, diluting the mixture with water, neutralizing any acid reaction present by the addition of an'alkaline substance, precipitating out the calcium by phosphoric acid, filtering, boiling until but slight or no odors are detected, diluting during such boiling to keep the water content at approximately eight-y per cent, filtering, concentrating, and finally recovering the sugar by crystallization HEBER C. CUTLER. 

